Mic Archive
Neumann M 50
Photo: Neumann, from its other, p. 1.

Neumann

Neumann M 50

Tube condenser, omni: a small pressure capsule set flush in a perspex sphere, so it grows directional at high frequencies; the Decca tree mic. Made 1951 to 1971, discontinued

Approximate Some readings for this mic are uncertain; see the graphs.

Type
Condenser
Pattern
Omni
Sensitivity
−36.5 dBV/Pa computed
Max SPL
126 dB SPL
Impedance
200 Ω
Rated range
40 – 16k Hz

Frequency response

Angle
Distance

Frequency response: from the catalog, p. 7. M 50 c, as printed in the 1964 brochure: no measuring conditions stated (free field presumably; the brochure says the response rises at the high end by about 5 dB and is almost linear in a diffuse field).

Dashed: outside the rated range, or simulated (other angles and distances). Hover or tap the graphs for values.

Polar pattern

Polar pattern: from the catalog, p. 8. M 50 c, 1964 brochure; no measuring conditions stated. Rings every 5 dB down to -20 dB. Both halves drawn; the two are averaged here. Approximate reading error up to about 1 dB; some frequencies are identified by reasoning, not by the legend: 10k Hz, 15k Hz.

Compare with other mics

All specs

From the catalog
CapsuleSmall pressure capsule with a metal diaphragm, mounted flush in a perspex sphere. "equipped with a metal diaphragm and mounted inside a perspex sphere". The history sheet: originally a highly stretched aluminium diaphragm, later gold-sputtered polyester foil, 10 µm from the backplate.p. 3
Sensitivity−36.5 dBV/Pa (15 mV/Pa), into 1000 ohm; also −40 dBV/Pa, M 50 b, 1960 manual (1.0 mV per dyne/cm²). Not stated by the manufacturer: From 1.5 mV/µbar = 15 mV/Pa: 20·log10(0.015).p. 6
Max SPL126 dB SPL, 0.5% distortion at 40 Hz, 1 kHz and 5 kHz; "≧ 126 dB"; also 114 dB SPL, M 50 b, 1960 manual: THD less than 0.6% (40-15,000 cps) up to 114 dB. "Max. sound pressure for .5% distortion at 40 cps, 1 kcps and 5 kcps ≧ 126 dB (dB above 2·10⁻⁴ µb)", i.e. re 20 µPa.
Output impedance200 ohm, ±20%; 50 ohm with two links changed on the output transformer; also 50 ohm, strapped for 50 ohm (output 6 dB lower; marked with a red dot). "Electrical source resistance 200 (50) Ω ± 20 %"; p. 3 explains the 50 ohm strapping.
Rated load impedance1000 ohm, minimum; 250 ohm when strapped for 50 ohm. "Electrical load resistance ≧ 1 000 (250) Ω".
Rated frequency range40 Hz to 16 kHz; also [40, 15000], M 50 b, 1960 manual: "Useable range of frequencies". "Frequency response 40 ... 16 000 cps". P. 3: in a diffuse field "an almost linear frequency response from 40 to 15 000 cps".
Poweringexternal tube supply: NN 48 b mains unit (4 V heater, 116 V plate), N 52 t plug-in unit or BB 50 battery unit. Accessories (p. 3, p. 4). Operating voltages from the 1960 manual (p. 1): "4 volts D.C. heater; 116 volts D.C. plate".p. 3
Connector8-pin Tuchel plug with bayonet locking. Supplied as M 250 c with RF-proof 7-pole standard couplings (Tuchel contact system).p. 2
Weight800 g. ".8 kg".p. 6
Dimensions163 × 80 mm. Length 163 mm, diameter 80 mm.
TubeTelefunken AC 701 k triode, as anode amplifier into an astatically wound transformer
Capacitance of capsuleapprox. 75 pF
Total noise voltage≦ 16 µV
Weighted noise voltage (DIN 45 405)≦ 7 µV
Equivalent loudness (DIN 45 405)≦ 28 dB (re 2·10⁻⁴ µbar)
Gain of microphone amplifier at 1 kHzapprox. -1 dB
ResponseRises evenly by about 5 dB towards high frequencies without becoming too directional; almost linear from 40 Hz to 15 kHz in a diffuse fieldp. 3
IdentificationWhite dot above the Neumann badge (the M 49 has a red one); same body as the M 49p. 2
UseOrchestras in acoustically favourable rooms with one microphone; spot mic for woodwind, brass and strings
AccessoriesNN 48 b power supply, N 52 t plug-in power supply (up to ten in an S 167 frame), BB 50 battery unit, C 26 / C 28 s cables (10 m), MZ 49 suspensionp. 3
From the m50v manual
VersionsM 50 (1951), M 50 b (documents of 1959-60), M 50 c (1964 brochure); Neumann's re-edition is the M 50 Vp. 8
From the product page
Decca treeThe M 50 "was instrumental in developing the Decca tree recording technique"

Documents

Copies kept by Mic Archive, because manufacturers move and drop their documents. Each is © Neumann, unchanged, with its original address.

Product page on neumann.comRecording Hacks

Recommended for

Instruments whose sources name this mic, or an earlier version or variant of it.

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